Class: RBarcode::Postnet

Inherits:
Base
  • Object
show all
Defined in:
lib/rbarcode/postnet.rb

Overview

This class takes a string and generates a Code 39-based barcode from that string.

Direct Known Subclasses

Planet

Constant Summary collapse

API_VERSION = 
"0.1"
BAR_SHORT_HEIGHT = 
7
BAR_TALL_HEIGHT = 
15
BAR_WIDTH = 
2
@@encoding =

@@encoding key

  • t => tall bar

  • s => short bar

{
  '0' => "ttsss",
  '1' => "ssstt",
  '2' => "sstst",
  '3' => "sstts",
  '4' => "stsst",
  '5' => "ststs",
  '6' => "sttss",
  '7' => "tssst",
  '8' => "tssts",
  '9' => "tstss"
}

Instance Attribute Summary

Attributes inherited from Base

#required, #text

Instance Method Summary collapse

Methods inherited from Base

#code39, #postnet

Constructor Details

#initialize(options = {}) ⇒ Postnet

Pass it a hash with :text => number



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# File 'lib/rbarcode/postnet.rb', line 33

def initialize(options = {})
  @required =  [:text]
  super
  @text.split(//).each do |char|
    if not @@encoding.has_key?(char)
      raise "Unencodable string."
    end
  end
  @text = "#{@text}"
end

Instance Method Details

#to_img(filename) ⇒ Object

RMagic image generation code Barcode image width and height should be in pixels.



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# File 'lib/rbarcode/postnet.rb', line 55

def to_img(filename)
  bar_code_width = @text.length * 2 * 5 * BAR_WIDTH + BAR_WIDTH * 3;

  #canvas = Image.new(width, height)
  canvas = Image.new(bar_code_width, BAR_TALL_HEIGHT)
  gc = Draw.new
  gc.fill('black')
  gc.stroke('black')
  gc.stroke_width(-1)
  # Necessary to prevent massive blurry image nonsense.
  gc.stroke_antialias(false)

  cur_x = 0

  # draw the start framing bar
  gc.rectangle(cur_x, 0, cur_x + BAR_WIDTH, BAR_TALL_HEIGHT)
  cur_x += BAR_WIDTH * 2

  #stsst ttsss ssstt sstst sstts stsst ststs sstst sstts ststs sttss sstts sttss sttss
  self.to_s.split(//).each do |char|
    if char == 't'
      gc.rectangle(cur_x, 0, cur_x + BAR_WIDTH, BAR_TALL_HEIGHT)
    else
      gc.rectangle(cur_x, (BAR_TALL_HEIGHT - BAR_SHORT_HEIGHT), cur_x + BAR_WIDTH, BAR_TALL_HEIGHT)
    end
    cur_x += BAR_WIDTH * 2
  end

  # draw the end framing bar
  gc.rectangle(cur_x, 0, cur_x + BAR_WIDTH - 1, BAR_TALL_HEIGHT)
  cur_x += BAR_WIDTH * 2

  gc.draw(canvas)
  canvas.write(filename)
end

#to_s ⇒ Object

Passes back encoding



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# File 'lib/rbarcode/postnet.rb', line 45

def to_s
  output = ''
  @text.split(//).each do |char|
    output += @@encoding[char]
  end
  return output
end